Hi, Mr/Mrs,
I am trying to use UART of TMS320F28335 and start with the example.
Now I found that this code can not be fished because it stuck after wrote two words to the TXBUF.
It is stuck by the following code. After writing two words to TXBUF, ScibRegs.SCIFFTX.bit.TXFFST = 1, and code stuck.
// Transmit a character from the SCI
void scib_xmit(int a)
{
while (ScibRegs.SCIFFTX.bit.TXFFST != 0) {}
ScibRegs.SCITXBUF=a;
}
I thought the TXBUF has 16 words space and be written 16 words before it is full.
Also, I can not observe the transmission waveform using oscilloscope on the TX pin of the two words written to TXBUF.
What does the problem mean? How to fix it? how to observe the transmission data waveform?
Thank you.
below is the code I used.
//###########################################################################
// ±¾Àý³ÌʵÏÖ£ºDSPͨ¹ý9Õë´®¿Ú£¨Ò²¾ÍÊÇSCI£©ÓëµçÄÔµÄ9Õë´®¿Ú½øÐд®ÐÐͨÐÅ
//###########################################################################
#include "DSP28x_Project.h" // Device Headerfile and Examples Include File
// Prototype statements for functions found within this file.
void scib_echoback_init(void);
void scib_fifo_init(void);
void scib_xmit(int a);
void scib_msg(char *msg);
// Global counts used in this example
Uint16 LoopCount;
Uint16 ErrorCount;
void main(void)
{
Uint16 ReceivedChar;
char *msg;
// Step 1. Initialize System Control:
// PLL, WatchDog, enable Peripheral Clocks
// This example function is found in the DSP2833x_SysCtrl.c file.
InitSysCtrl();
// Step 2. Initalize GPIO:
// This example function is found in the DSP2833x_Gpio.c file and
// illustrates how to set the GPIO to it's default state.
// InitGpio(); Skipped for this example
// For this example, only init the pins for the SCI-A port.
// This function is found in the DSP2833x_Sci.c file.
InitScibGpio();
// Step 3. Clear all interrupts and initialize PIE vector table:
// Disable CPU interrupts
DINT;
// Initialize PIE control registers to their default state.
// The default state is all PIE interrupts disabled and flags
// are cleared.
// This function is found in the DSP2833x_PieCtrl.c file.
InitPieCtrl();
// Disable CPU interrupts and clear all CPU interrupt flags:
IER = 0x0000;
IFR = 0x0000;
// Initialize the PIE vector table with pointers to the shell Interrupt
// Service Routines (ISR).
// This will populate the entire table, even if the interrupt
// is not used in this example. This is useful for debug purposes.
// The shell ISR routines are found in DSP2833x_DefaultIsr.c.
// This function is found in DSP2833x_PieVect.c.
InitPieVectTable();
// Step 4. Initialize all the Device Peripherals:
// This function is found in DSP2833x_InitPeripherals.c
// InitPeripherals(); // Not required for this example
// Step 5. User specific code:
LoopCount = 0;
ErrorCount = 0;
scib_fifo_init(); // Initialize the SCI FIFO
scib_echoback_init(); // Initalize SCI for echoback
msg = "\r\n\Welcome to use ZQ28335 (www.00ic.com)\0";
scib_msg(msg);
msg = "\r\nYou will enter a character, and the DSP will echo it back! \n\0";
scib_msg(msg);
ScibRegs.SCIFFRX.bit.RXFFOVRCLR=1;
for(;;)
{
msg = "\r\nEnter a character: \0";
scib_msg(msg);
// Wait for inc character
while(ScibRegs.SCIFFRX.bit.RXFFST !=1) { } // wait for XRDY =1 for empty state
// Get character
ReceivedChar = ScibRegs.SCIRXBUF.all;
// Echo character back
msg = " You sent: \0";
scib_msg(msg);
scib_xmit(ReceivedChar);
LoopCount++;
}
}
// Test 1,SCIA DLB, 8-bit word, baud rate 0x000F, default, 1 STOP bit, no parity
void scib_echoback_init()
{
// Note: Clocks were turned on to the Scib peripheral
// in the InitSysCtrl() function
//ScibRegs.SCICCR.all =0x0007; // 1 stop bit, No loopback
// No parity,8 char bits,
// async mode, idle-line protocol
// revised by ZC 10262018
ScibRegs.SCICCR.all =0x0087; // 2 stop bit, No loopback
// No parity,8 char bits,
// async mode, idle-line protocol
ScibRegs.SCICTL1.all =0x0003; // enable TX, RX, internal SCICLK,
// Disable RX ERR, SLEEP, TXWAKE
ScibRegs.SCICTL2.all =0x0003;
ScibRegs.SCICTL2.bit.TXINTENA =1;
ScibRegs.SCICTL2.bit.RXBKINTENA =1;
#if (CPU_FRQ_150MHZ)
ScibRegs.SCIHBAUD =0x0001; // 9600 baud @LSPCLK = 37.5MHz.
ScibRegs.SCILBAUD =0x00E7;
#endif
#if (CPU_FRQ_100MHZ)
ScibRegs.SCIHBAUD =0x0001; // 9600 baud @LSPCLK = 20MHz.
ScibRegs.SCILBAUD =0x0044;
#endif
ScibRegs.SCICTL1.all =0x0023; // Relinquish SCI from Reset
}
// Transmit a character from the SCI
void scib_xmit(int a)
{
while (ScibRegs.SCIFFTX.bit.TXFFST != 0) {}
ScibRegs.SCITXBUF=a;
}
void scib_msg(char * msg)
{
int i;
i = 0;
while(msg[i] != '\0')
{
scib_xmit(msg[i]);
i++;
}
}
// Initalize the SCI FIFO
void scib_fifo_init()
{
ScibRegs.SCIFFTX.all=0xE040;
ScibRegs.SCIFFRX.all=0x204f;
ScibRegs.SCIFFCT.all=0x0;
}
//===========================================================================
// No more.
//===========================================================================
